The subject of the present invention is a control method for activating a control device designed to be incorporated into a starter for a combustion engine, the device comprising a solenoid controlling the position of a pinion of the starter suitable for being engaged in a ring gear kinematically associated with a crankshaft of said engine, said pinion being able to be driven by an electric motor of the starter by closing a first switched power supply channel between a battery and the starter, the device also comprising an auxiliary relay and at least one power resistor placed in series creating a second switched power supply channel in parallel with said first switched channel and making it possible to power, via a power supply current that is weaker than the maximum current, the electric motor of the starter driving said pinion.
This invention falls within the context of current automobile technology, notably the context of the starters of heat engines having the functionality commonly called “Stop & Start”. This functionality consists in automatically stopping the engine when the vehicle speed is zero, for example when stopped at a red light or in any other situation requiring the vehicle to stop, the engine subsequently being restarted automatically when the user activates it again. The object of this is to reduce the consumption of the vehicle and the pollution that it generates. In order to achieve this “Stop & Start” function also called “S&S” on a vehicle with a heat engine, notably on an automobile, while retaining a simple onboard electric system, normally a 14V system, there are currently mainly two possibilities based on electro-magnetic automobile starting members. Either an alternator-starter is used which is a reversible machine placed on the belt of the engine or a starter is used suitable for the S&S function with respect to power, noise, wear, etc. This type of starter, during the starting phase until the engine is running independently through the combustion cycles, drives the crankshaft of the heat engine via a pinion which engages on the teeth of a ring gear mounted on the periphery of the engine flywheel, the engagement of the pinion in the ring being controlled by a solenoid arranged in the starter.
The use of an S&S starter mentioned above provides a very marked potential to reduce cost relative to an alternator-starter and is of value notably for generalist automobile manufacturers who are concerned about the cost-benefit ratio of their products. This kind of starter has been improved in the past, for example in the control of the current of its solenoid, for which an electronic chopper as explained in documents DE 10 034 779 and U.S. Pat. No. 5,818,679 has been proposed, in order to achieve a progressive engagement of the pinion in two stages, see for example documents U.S. Pat. No. 6,104,157 and U.S. Pat. No. 6,323,562. Similarly, a solenoid having a single coil with two stages has been proposed for such a starter.
A control device designed to be incorporated into such a starter and corresponding to the kind mentioned above has also been produced by the applicant and is the subject of patent application FR 0 606 740. This control device makes it possible to limit the power consumed by the electric starter during the starting of the combustion engine, by clipping the current when the starter is switched on.
Currently, the automobile manufacturers are seeking to further improve this kind of “Stop & Start” starter, in particular because it would be desirable to have additionally a function called “reflex-start”. The “reflex-start” function consists in restarting the engine via the starting member while the engine crankshaft, unlike the situation of a usual starter, is not immobilized, following a rapid succession of instructions, for example following a stop and then a restart in less than a second. This kind of situation may notably occur in the event of the immobilization of an automobile at a red light that has just switched to green, during a change of speed when entering a rotary intersection or a give-way point, etc. The aforementioned alternator-starter system makes it possible to carry out the “reflex-start” function because the coupling via the belt of the reversible electric machine with the crankshaft of the engine naturally synchronizes the rotation speed of the machine with the crankshaft, give or take the drive ratio. It is therefore sufficient to power the electric machine in order to supply immediately, that is to say as soon as the currents in the electric machine are established, a drive torque to the heat engine. But, as mentioned above, the cost of an alternator-starter remains high relative to an S&S starter, thus pushing the automobile manufacturers to find an alternative solution.
On the other hand, the current S&S starters, respectively their control devices, do not make it possible to perform such a “reflex-start” function because this requires a synchronization of the rotation speeds of the pinion and of the ring before their mutual engagement, the engine, respectively the crankshaft, again rotating in this constellation. A starter fitted with a normal solenoid starter drive assembly actually powers the electric motor driving said pinion of the starter only when the core of the solenoid is at the end of its travel, that is to say when the pinion is engaged or otherwise in a tooth-against-tooth position with said ring gear followed by an engagement. An operation of engaging the pinion on a ring in rotation risks causing the teeth of the pinion to rebound against the teeth of the ring with noise and wear effects and even breakage of teeth which is unacceptable.